This invention concerns a stabilizer for deep well drilling tools.
With a known stabilizer of this type (U.S. Pat. No. 4,407,377), the ribbed bodies fit tightly in the slit openings of the outer casing and are sealed with respect to the slit openings. The outer longitudinal and end faces of the ribbed bodies thus form guide faces that are in sliding engagement with the inside faces of the slit openings opposite them as mating faces. The ribbed bodies are provided with projections that extend outward along the internal longitudinal edges and act as stops together with the casing to set an outer limit position for the ribbed bodies. The ribbed bodies move radially outward out of a flush starting position in the slit openings into a working position or an outer end position against the force of leaf springs that are braced on the casing and tend to push the ribbed bodies back into their flush starting position. With such a stabilizer, the ribbed bodies have a tendency to stick in the slit openings and fail to return to their starting position because even minor tilting leads to jamming, and furthermore there is the danger that solids such as rock particles in the oil well fluid might stick between the guide faces and block the shifting movements of the ribbed bodies.